In-App Purchase simulator - License information gone after navigate

Question

hi everyone.

i'm trying to add in-app purchase in my application. but when i navigate to mainpage from purchase page after purchased product and navigate back to purchase page my licenseinfo lost(i think). i can purchase same product again after navigate.  sorry for my english and let me insert my codes here.

where is my mistake.

thanks.

Windows.Storage.ApplicationDataContainer localSettings = Windows.Storage.ApplicationData.Current.LocalSettings;
        Windows.Storage.StorageFolder localFolder = Windows.Storage.ApplicationData.Current.LocalFolder;

        LicenseChangedEventHandler licenseChangeHandler = null;

        /// ///////////////////////////////////////////

        public SatinAlma()
        {
            this.InitializeComponent();
            
        }

private async Task LoadInAppPurchaseProxyFileAsync()
        {

            StorageFolder proxyDataFolder = await Package.Current.InstalledLocation.GetFolderAsync("Data");
            StorageFile proxyFile = await proxyDataFolder.GetFileAsync("in-app-purchase.xml");
            licenseChangeHandler = new LicenseChangedEventHandler(InAppPurchaseRefreshScenario);
            CurrentAppSimulator.LicenseInformation.LicenseChanged += licenseChangeHandler;
            await CurrentAppSimulator.ReloadSimulatorAsync(proxyFile);


            // setup application upsell message
            try
            {
                ListingInformation listing = await CurrentAppSimulator.LoadListingInformationAsync();

                var PurchasePzl9 = listing.ProductListings["puzzle9"];
                var PurchasePzl16 = listing.ProductListings["puzzle16"];
                var PurchasePzl25 = listing.ProductListings["puzzle25"];
                var PurchaseYardimseverlik = listing.ProductListings["yardimseverlik"];
                var PurchaseTumpaket = listing.ProductListings["tumpaket"];
            }
            catch (Exception)
            {
                OAL_toast.showToast("LoadListingInformationAsync API call failed\n");
            }
        }


protected override void OnNavigatingFrom(NavigatingCancelEventArgs e)
        {
            if (licenseChangeHandler != null)
            {
                CurrentAppSimulator.LicenseInformation.LicenseChanged -= licenseChangeHandler;
            }
            base.OnNavigatingFrom(e);
        }
        protected override async void OnNavigatedTo(NavigationEventArgs e)
        {
            await LoadInAppPurchaseProxyFileAsync();
        }

        private void InAppPurchaseRefreshScenario()
        {

        }


private async void purchaseProduct()
        {
            LicenseInformation licenseInformation = CurrentAppSimulator.LicenseInformation;
            if (!licenseInformation.ProductLicenses[stringPurchaseProduct].IsActive)
            {
                try
                {
                    await CurrentAppSimulator.RequestProductPurchaseAsync(stringPurchaseProduct);
                    if (licenseInformation.ProductLicenses[stringPurchaseProduct].IsActive)
                    {
                        OAL_toast.showToast(stringPurchaseProduct + " purchased.");
                        OptimeAnimationLib.MsgBox(stringPurchaseProduct + " purchased.");
                        this.Frame.Navigate(typeof(MainPage));
                    }
                    else
                    {
                        OptimeAnimationLib.MsgBox(stringPurchaseProduct + " was not purchased.");
                        OAL_toast.showToast(stringPurchaseProduct + " was not purchased.");

                    }
                }
                catch (Exception)
                {
                    OAL_toast.showToast("Unable to buy " + stringPurchaseProduct);

                }
            }
            else
            {
                OAL_toast.showToast("you already own " + stringPurchaseProduct);

            }
        }


private void IMG_puzzle9_PointerReleased(object sender, PointerRoutedEventArgs e)
        {
            LicenseInformation licenseInformation = CurrentAppSimulator.LicenseInformation;
            var productLicense = licenseInformation.ProductLicenses["puzzle9"];
            if (productLicense.IsActive)
            {
                OAL_toast.showToast("you already own Puzzle 9.");
            }
            else
            {
                stringPurchaseProduct = "puzzle9";
                sayilariGoster();
            }

        }